$ ./ClashCalc.py 
    test_data/no_clash.pdb
    Contacts, str_name: 17 98 test_data/no_clash.pdb Sterical clashes  0.173469387755
    test_data/super_clash.pdb
    Contacts, str_name: 877 1208 test_data/super_clash.pdb Sterical clashes  0.725993377483